Study On The Mechanism Of Groundwater And Control Measures Of GuanJia Landslide

Guanjia landslide is a typical debris landslide, which developed widespread in southern of china.Groundwater is one of the most significant factors affecting the deformation and the stability of slope. Pipe drainage of groundwater is often developed in the debris slopes in Zhejiang province and is important in restricting groundwater level rising and in keeping slope stability. Cutting at slope toe or loading on slope surface may destroy the pipe seepage system and make groundwater level rise obviously. As a result, the pore water pressure on a potential slip surface will rise and a landslide may take place. The deformation and failure of debris landslide is a slow-developing process and may re-collapse. Based on the field investigation and theory analysis, the paper has presented the practical and usefully treatment for debris landslide.The influence of the groundwater seepage on soil mass comes to be true through the seepage force on the soil grain. According to the formula of the seepage force, it can be deduced that the seepage force only lies on the hydraulic gradient. The sections of different utilization degrees of share strength are determined by saturation-area ratio. Based on it, improved transport coefficient method is presented which can more reflect actual locating state of debris landslide. After the first deformation, a new pipe drainage system will establish. Then, water level depression will generate seepage force which is disadvantage for the stability of slope. The downslide force can be increased with the seepage force in slope mass as the seepage, which has a bad effect on the stability of slope. The paper simulates the stability of slope considering the seepage and without it by the finite element software and evaluates quantificationally the effect degree of the seepage on the stability of slope.Rainfall is the main induced factor for deformation and recollapse of debris slope. Focusing on the problems in the present landslide treatment measures and combining with sensitivity analysis on destroy mechanism of debris slope; a new control strategy is presented that is the drainage of groundwater shall be the major measure to increase thestability of debris landslide.